uses TLHelp32;

function IsExeRunning(const AExeName: string): boolean;
var
  h: THandle;
  p: TProcessEntry32;
begin
  Result := False;

  p.dwSize := SizeOf(p);
  h := CreateToolHelp32Snapshot(TH32CS_SnapProcess, 0);
  try
    Process32First(h, p);
    repeat
      Result := AnsiUpperCase(AExeName) = AnsiUpperCase(p.szExeFile);
    until Result or (not Process32Next(h, p));
  finally
    CloseHandle(h);
  end;
end;

function KillTask(const AExeName: string): boolean;
var
  p: TProcessEntry32;
  h: THandle;
begin
  Result := false;
  p.dwSize := SizeOf(p);
  h := CreateToolHelp32Snapshot(TH32CS_SnapProcess, 0);
  try
    if Process32First(h, p) then
      repeat
        if AnsiLowerCase(p.szExeFile) = AnsiLowerCase(AExeName) then
          Result := TerminateProcess(OpenProcess(Process_Terminate,
                                                 false,
                                                 p.th32ProcessID),
                                     0);
      until (not Process32Next(h, p)) or Result;
  finally
    CloseHandle(h);
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
 while isexerunning('myProgram.exe') do KillTask('myProgram.exe');
end;